Thyroid Hormone Stereochemistry. III. Molecular Structure of Triiodothyropropionic Acid Ethyl Ester

1974 ◽  
Vol 52 (17) ◽  
pp. 3048-3053 ◽  
Author(s):  
Norman Camerman ◽  
Arthur Camerman
Keyword(s):  
Ethyl Ester ◽  
Iodine Atom ◽  
Molecular Conformation ◽  
Three Dimensional ◽  
Acid Ethyl Ester ◽  
Dimensional Structure ◽  
Monoclinic Space Group ◽  
Ether Linkage ◽  
Cell Dimensions ◽  
Phenyl Rings

The three-dimensional structure of triiodothyropropionic acid ethyl ester has been determined as part of an investigation of the stereochemistry of the thyroid hormones. The compound crystallizes in the monoclinic space group P21/c, with cell dimensions a = 14.60, b = 8.843, c = 16.70 Å, β = 111°27′; Z = four molecules per cell. The structure was determined by direct centrosymmetric phasing procedures to locate the iodine atoms and phasing on the iodines to find the light atoms. Refinement was by anisotropic full-matrix least squares to a final discrepancy value R = 0.038.The two phenyl rings in the molecule are skewed with respect to each other and are not far from being mutually perpendicular, with angles of 88 and 10° between the plane of the inter-ring ether linkage and the planes of the diiodo-ring and the monoiodo-ring, respectively. The conformation is such that the 3′-iodine atom is proximal to the diiodo-ring, similar to the molecular conformation found in the crystal structure of triiodo-L-thyronine hydrochloride.

Thyroid Hormone Stereochemistry. II. Molecular Structure of Thyronine HCl Ethyl Ester Monohydrate

1974 ◽  
Vol 52 (17) ◽  
pp. 3042-3047 ◽  
Author(s):  
Arthur Camerman ◽  
Norman Camerman
Keyword(s):  
Ethyl Ester ◽  
Three Dimensional ◽  
Chloride Ion ◽  
Dimensional Structure ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Ether Linkage ◽  
Cell Dimensions ◽  
Phenyl Rings

The three-dimensional structure of L-thyronine, the non-iodinated physiologically inactive analog of thyroxine, has been determined by single crystal X-ray diffraction and compared to the active thyroid hormones. The compound crystallized as the monohydrate of thyronine hydrochloride ethyl ester in the monoclinic space group P21 with cell dimensions a = 10.502, b = 5.165, c = 17.940 Å, β = 109.74°. The structure was solved by Patterson methods to find the chloride ion and iterative Fourier maps to locate the rest of the atoms. Refinement was by anisotropic full-matrix least squares to convergence at R = 0.048.The two phenyl rings adopt a twisted orientation with respect to each other with angles of −37° and −67° between the plane of the inter-ring ether linkage and the planes of the α- and β-rings, respectively. This orientation differs considerably from that found in the iodinated thyronines. The conformation of the alanine side chain is remarkably similar to that of the alanine in the iodinated thyronines.

Structure and conformation of the anticodon nucleoside 5-methoxyuridine in the solid state and in solution

1983 ◽  
Vol 61 (10) ◽  
pp. 2299-2304 ◽  
Author(s):  
George I. Birnbaum ◽  
Wayne J. P. Blonski ◽  
Frank E. Hruska
Keyword(s):  
Solid State ◽  
Three Dimensional ◽  
Direct Methods ◽  
Pyrimidine Ring ◽  
Dimensional Structure ◽  
Side Chain ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Cell Dimensions ◽  
Enol Tautomer

The three-dimensional structure of 5-methoxyuridine (mo5U) was determined with much higher precision than in a previous study (Hillen etal. J. Carbohydr. Nucleosides Nucleotides, 5, 23 (1978)). The crystals belong to the monoclinic space group P21 and the cell dimensions are a = 8.916(2), b = 14.372(2), c = 4.714(1) Å, β = 97.44(2)°. Intensity data were measured with a diffractometer and the structure was solved by direct methods. Least-squares refinement, which included all hydrogen atoms, converged at R = 0.031. The conformation about the glycosyl bond is anti (χCN = 23.1°), the pucker of the ribose ring is C(3′)endo, and the conformation of the —CH2OH side chain is gauche+. A comparison of the bond lengths N(3)—C(4) and C(4)—O(4) with those in uridine does not support the conclusion of Hillen etal. about a shift to the enol tautomer in mo5U. However, there are other changes in the geometry of the pyrimidine ring due to substitution at C(5). A conformational analysis, based on 1H and 13C nmr data, shows that the preferred conformation in solution is that observed in the solid state.

scholarly journals Synthesis and crystal structure of a new polymorph of potassium europium(III) bis(sulfate) monohydrate, KEu(SO4)2·H2O

2018 ◽  
Vol 74 (2) ◽  
pp. 242-245 ◽  
Author(s):  
Avijit Kumar Paul
Keyword(s):  
Crystal Structure ◽  
Topological Analysis ◽  
Structural Connectivity ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Monoclinic Space Group ◽  
Hydrothermal Conditions ◽  
Metal Sulfate ◽  
Synthesis And Crystal Structure ◽  
Trigonal Prismatic

The mixed-metal sulfate, KEu(SO4)2·H2O, has been obtained as a new polymorph using hydrothermal conditions. The crystal structure is isotypic with NaCe(SO4)2·H2O and shows a three-dimensional connectivity of the tetrahedral sulfate units with EuIII and KI ions. Tricapped trigonal–prismatic EuO9 units and square-antiprismatic KO8 units link the SO4 tetrahedra, building the three-dimensional structure. Topological analysis reveals the existence of two nodes with 6- and 10-connected nets. The compound was previously reported [Kazmierczak & Höppe (2010). J. Solid State Chem. 183, 2087–2094] in the monoclinic space group P21/c with a similar structural connectivity and coordination environments to the present compound.

scholarly journals Crystallization and preliminary X-ray analysis of the major peanut allergen Ara h 1 core region

2010 ◽  
Vol 66 (9) ◽  
pp. 1071-1073 ◽  
Author(s):  
Cerrone Cabanos ◽  
Hiroyuki Urabe ◽  
Taro Masuda ◽  
Mary Rose Tandang-Silvas ◽  
Shigeru Utsumi ◽  
...  
Keyword(s):  
Sodium Citrate ◽  
Three Dimensional ◽  
Core Region ◽  
Dimensional Structure ◽  
Monoclinic Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Peg 400 ◽  
Ara H 1 ◽  
Peanut Allergens

Peanuts contain some of the most potent food allergens known to date. Ara h 1 is one of the three major peanut allergens. As a first step towards three-dimensional structure elucidation, recombinant Ara h 1 core region was cloned, expressed inEscherichia coliand purified to homogeneity. Crystals were obtained using 0.1 Msodium citrate pH 5.6, 0.1 MNaCl, 15% PEG 400 as precipitant. The crystals diffracted to 2.25 Å resolution using synchrotron radiation and belonged to the monoclinic space groupC2, with unit-cell parametersa= 156.521,b= 88.991,c= 158.971 Å, β = 107.144°. Data were collected at the BL-38B1 station of SPring-8 (Hyogo, Japan).

Structure and Fluorescence Properties of a Novel Supramolecular Zinc Complex

2008 ◽  
Vol 63 (12) ◽  
pp. 1357-1360 ◽  
Author(s):  
Gang Chen
Keyword(s):  
Hydrothermal Reaction ◽  
Three Dimensional ◽  
Free Ligand ◽  
Distorted Octahedral Geometry ◽  
Monoclinic Space Group ◽  
Ligand Complex ◽  
Complex Molecules ◽  
Hydrogen Bonding Interactions ◽  
Distorted Octahedral ◽  
Cell Dimensions

Hydrothermal reaction of Zn(NO3)2 · 6H2O and 2-hydroxypyridine-3-carboxylic acid afforded a novel supramolecular complex, [Zn(C6H4NO3)2(H2O)2] (1). The complex has been characterized by macroanalysis, IR spectra, and thermogravimetric and differential thermal analysis (TG/DTA). Single crystal X-ray analysis shows that complex 1 crystallizes in the monoclinic space group P21/c with the cell dimensions a = 7.534(6), b = 12.289(1), c = 7.534(6) Å, β = 100.51°, V = 685.85(1) Å3, and Z = 2. The six-coordinated Zn atom is in a severely distorted octahedral geometry. The complex molecules are assembled via strong O-H· · ·O and N-H· · ·O hydrogen bonding interactions into a three-dimensional supramolecular framework. Compared with the free ligand, complex 1 exhibits strong fluorescence in the solid state at room temperature.

Structure and conformation of the hydrochloride of pseudoisocytidine, an antileukemic C-nucleoside

1980 ◽  
Vol 58 (16) ◽  
pp. 1633-1638 ◽  
Author(s):  
George I. Birnabaum ◽  
Kyoichi A. Watanabe ◽  
Jack J. Fox
Keyword(s):  
Heavy Atom ◽  
Three Dimensional ◽  
Direct Methods ◽  
Dimensional Structure ◽  
Side Chain ◽  
Hydrogen Atoms ◽  
Triclinic Space Group ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Sugar Ring

The three-dimensional structure of pseudoisocytidine hydrochloride was determined by X-ray crystallography. The crystals belong to the triclinic space group P1 and the cell dimensions are a = 6.623(2), b = 8.053(2), c = 6.201(2) Å, α = 108.35(2), β = 101.36(2), γ = 93.54(2) °. Intensity data were measured with a diffractometer and the structure was solved by a combination of heavy-atom and direct methods. Least-squares refinement, which included hydrogen atoms, converged at R = 0.040. The conformation about the glycosyl bond is anti (χCC = 21.6°), the pucker of the furanose ring is C(1′)exo, and the conformation of the —CH2OH side chain is gauche–trans (t). An examination of bond lengths indicates that of the three main resonance forms of the isocytosine cation the fully conjugated one contributes more to the structure than the cross-conjugated one. Bond angles in the sugar ring reflect its rare conformation.

scholarly journals Crystal structures of 2-aminopyridine citric acid salts: C5H7N2 +·C6H7O7 − and 3C5H7N2 +·C6H5O7 3−

2018 ◽  
Vol 74 (8) ◽  
pp. 1111-1116 ◽  
Author(s):  
Shet M. Prakash ◽  
S. Naveen ◽  
N. K. Lokanath ◽  
P. A. Suchetan ◽  
Ismail Warad
Keyword(s):  
Hydrogen Bond ◽  
Citric Acid ◽  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Crystal Engineering ◽  
Molecular Conformation ◽  
Crystal Packing ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Almost All

2-Aminopyridine and citric acid mixed in 1:1 and 3:1 ratios in ethanol yielded crystals of two 2-aminopyridinium citrate salts, viz. C5H7N2 +·C6H7O7 − (I) (systematic name: 2-aminopyridin-1-ium 3-carboxy-2-carboxymethyl-2-hydroxypropanoate), and 3C5H7N2 +·C6H5O7 3− (II) [systematic name: tris(2-aminopyridin-1-ium) 2-hydroxypropane-1,2,3-tricarboxylate]. The supramolecular synthons present are analysed and their effect upon the crystal packing is presented in the context of crystal engineering. Salt I is formed by the protonation of the pyridine N atom and deprotonation of the central carboxylic group of citric acid, while in II all three carboxylic groups of the acid are deprotonated and the charges are compensated for by three 2-aminopyridinium cations. In both structures, a complex supramolecular three-dimensional architecture is formed. In I, the supramolecular aggregation results from Namino—H...Oacid, Oacid...H—Oacid, Oalcohol—H...Oacid, Namino—H...Oalcohol, Npy—H...Oalcohol and Car—H...Oacid interactions. The molecular conformation of the citrate ion (CA3−) in II is stabilized by an intramolecular Oalcohol—H...Oacid hydrogen bond that encloses an S(6) ring motif. The complex three-dimensional structure of II features Namino—H...Oacid, Npy—H...Oacid and several Car—H...Oacid hydrogen bonds. In the crystal of I, the common charge-assisted 2-aminopyridinium–carboxylate heterosynthon exhibited in many 2-aminopyridinium carboxylates is not observed, instead chains of N—H...O hydrogen bonds and hetero O—H...O dimers are formed. In the crystal of II, the 2-aminopyridinium–carboxylate heterosynthon is sustained, while hetero O—H...O dimers are not observed. The crystal structures of both salts display a variety of hydrogen bonds as almost all of the hydrogen-bond donors and acceptors present are involved in hydrogen bonding.

A Proton Magnetic Resonance Study of the Effect of 2′-O-Methylation on Ribonucleoside Conformation

1973 ◽  
Vol 51 (7) ◽  
pp. 1099-1106 ◽  
Author(s):  
Frank E. Hruska ◽  
Alan Mak ◽  
Harwant Singh ◽  
David Shugar
Keyword(s):  
Proton Magnetic Resonance ◽  
Molecular Conformation ◽  
Chemical Shifts ◽  
Three Dimensional ◽  
Coupling Constants ◽  
Dimensional Structure ◽  
Aqueous Environment ◽  
Magnetic Resonance Study ◽  
Proton Magnetic Resonance Study ◽  
Methyl Derivatives

The 100- and 220- MHz p.m.r. spectra of uridine, cytidine, and their 2′-O-methyl derivatives are obtained in aqueous solution at several temperatures. The experimental chemical shifts and coupling constants are discussed in terms of the overall molecular conformation. The conclusion is reached that 2′-O-methylation has little effect upon the three-dimensional structure of a nucleoside at the monomer level in an aqueous environment.

scholarly journals Crystal structures ofN2,N3,N5,N6-tetrakis(pyridin-2-ylmethyl)pyrazine-2,3,5,6-tetracarboxamide andN2,N3,N5,N6-tetrakis(pyridin-4-ylmethyl)pyrazine-2,3,5,6-tetracarboxamide

2017 ◽  
Vol 73 (2) ◽  
pp. 300-305
Author(s):  
Dilovan S. Cati ◽  
Helen Stoeckli-Evans
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Monoclinic Space Group ◽  
Compound I ◽  
Acta Cryst ◽  
Pyrazine Ring ◽  
Bond Forming ◽  
Compound Ii

The title compounds, C32H28N10O4· unknown solvent, (I), and C32H28N10O4, (II), are pyrazine-2,3,5,6-tetracarboxamide derivatives. In (I), the substituents are (pyridin-2-ylmethyl)carboxamide, while in (II), the substituents are (pyridin-4-ylmethyl)carboxamide. Both compounds crystallize in the monoclinic space groupP21/n, withZ′ = 1 for (I), andZ′ = 0.5 for (II). The whole molecule of (II) is generated by inversion symmetry, the pyrazine ring being situated about a center of inversion. In (I), the four pyridine rings are inclined to the pyrazine ring by 83.9 (2), 82.16 (18), 82.73 (19) and 17.65 (19)°. This last dihedral angle involves a pyridine ring that is linked to the adjacent carboxamide O atom by an intramolecular C—H...O hydrogen bond. In compound (II), the unique pyridine rings are inclined to the pyrazine ring by 33.3 (3) and 81.71 (10)°. There are two symmetrical intramolecular C—H...O hydrogen bonds present in (II). In the crystal of (I), molecules are linked by N—H...O and N—H...N hydrogen bonds, forming layers parallel to (10-1). The layers are linked by C—H...O and C—H...N hydrogen bonds, forming a three-dimensional framework. In the crystal of (II), molecules are linked by N—H...N hydrogen bonds, forming chains propagating along the [010] direction. The chains are linked by a weaker N—H...N hydrogen bond, forming layers parallel to the (101) plane, which are in turn linked by C—H...O hydrogen bonds, forming a three-dimensional structure. In the crystal of compound (I), a region of disordered electron density was treated with the SQUEEZE routine inPLATON[Spek (2015).Acta Cryst. C71, 9–18]. Their contribution was not taken into account during refinement. In compound (II), one of the pyridine rings is positionally disordered, and the refined occupancy ratio for the disordered Car—Car—Npyatoms is 0.58 (3):0.42 (3).

scholarly journals Crystal structure of (Z)-2-(1-benzyl-2-oxoindolin-3-ylidene)-N-phenylhydrazine-1-carbothioamide

2015 ◽  
Vol 71 (3) ◽  
pp. o160-o161
Author(s):  
G. Vimala ◽  
J. Haribabu ◽  
R. Karvembu ◽  
B. V. N. Phani Kumar ◽  
A. SubbiahPandi
Keyword(s):  
Phenyl Ring ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Dihedral Angles ◽  
Asymmetric Unit ◽  
Compound C ◽  
Phenyl Rings ◽  
The Mean ◽  
Independent Molecules ◽  
Ring Motif

The title compound, C22H18N4OS, crystallized with four independent molecules (A,B,CandD) in the asymmetric unit. All four molecules have aZconformation about the C=N bond with the benzyl ring being inclined to the indoline ring mean planes by 73.4 (2), 77.9 (2), 73.2 (2) and 77.2 (2)° in moleculesA,B,CandD, respectively. In moleculesAandB, the phenyl ring is inclined to the mean plane of the indoline ring mean plane by 12.0 (2) and 12.2 (2)°, respectively. However, in moleculesCandD, the same dihedral angles are larger,viz.37.3 (2) and 36.4 (2)°, respectively. Consequently, the benzyl and phenyl rings are almost normal to one another in moleculesAandB[dihedral angles = 80.3 (3) and 87.1 (3)°, respectively], while in moleculesCandD, the same dihedral angles are only 48.8 (2) and 43.8 (3)°, respectively. There is an intramolecular N—H...O hydrogen bond in each molecule with anS(6) ring motif. There are also short intramolecular N—H...N and C—H...S contacts in each molecule. In the crystal, molecules are linkedviaC—H...S hydrogen bonds and C—H...π interactions, forming a three-dimensional structure. The crystal was refined as a non-merohedral twin with a final BASF value of 0.110 (1).

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